Q1: The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K= 0.04 W/m.°K and thickness 0.16m is 10 W/m². The temperature of the inside wall is - 5°C. The outside wall temperature is

ANS:C - 35°C

To find the outside wall temperature, we can use the formula for heat flux through a plane wall: totalQ=Rtotal​ΔT⋅A​ Where:

• Q is the heat flux (in W/m²),
• ΔT is the temperature difference across the wall (in °C),
• A is the area of the wall (in m²), and
• totalRtotal​ is the total thermal resistance of the wall (in m².°C/W).

The total thermal resistance of the wall (totalRtotal​) is given by: total=⋅Rtotal​=K⋅AL​ Where:

• L is the thickness of the wall (in meters), and
• K is the thermal conductivity of the wall material (in W/m.°C).

Given:

• Heat flux (Q) = 10 W/m²
• Thickness of the wall (L) = 0.16 m
• Thermal conductivity (K) = 0.04 W/m.°C
• Inside wall temperature = -5°C

First, we need to convert the inside wall temperature to Kelvin: inside=−5°+273.15=268.15Tinside​=−5°C+273.15=268.15K Now, we can find the temperature difference across the wall: Δ=outside−insideΔT=Toutside​−Tinside​ We rearrange the formula for heat flux to solve for the outside wall temperature: outside=Δ+insideToutside​=ΔT+Tinside​ Substituting the given values and solving: outside=+insideToutside​=LQ⋅K⋅A​+Tinside​ outside=10⋅0.04⋅10.16+268.15Toutside​=0.1610⋅0.04⋅1​+268.15 outside=0.40.16+268.15Toutside​=0.160.4​+268.15 outside=2.5+268.15Toutside​=2.5+268.15 outside=270.65 KToutside​=270.65K Converting back to Celsius: outside=270.65 K−273.15=−2.5°Toutside​=270.65K−273.15=−2.5°C So, the outside wall temperature is approximately -2.5°C. Since this is an unusual result (warmer outside temperature than inside temperature for heat flow from outside to inside), let's review the calculation. The heat flux formula and calculation steps are correct, but the unusual result may indicate an inconsistency or error in the problem setup or given data. Please double-check the problem statement or provide additional context if necessary.